We are submitting a revised application in response to the IRG Summary Statement of 4/16/96 to study the onset, early course, and patterns of service use of men and women seeking crisis treatment for an episode of DSM-IV psychotic disorder accompanied by drug use. It is designed to distinguish between substance-induced psychosis and primary psychosis that Co-occurs with drug use. Four hundred subjects who present to the psychiatric emergency service with psychotic symptoms of recent onset associated with the use of drugs will be evaluated over a five week intake period, contacted monthly for service use data, and interviewed again at six and twelve months. Diagnostic data include the intake facility diagnosis, the intake research diagnosis, and a "LEAD" diagnosis based on the multiple sources of data gathered over the one-year study period. Specific aims probe the concordance of the intake facility and research diagnoses and their relationship to antecedent characteristics, course of illness, and the match between diagnosis and type of treatment for substance use. Outcome of the match in the facility diagnosis and treatment prescription at intake will be studied over the ensuing twelve months in terms of the number of changes in type of treatment for substance use, engagement in treatment, number of psychotic episodes, use of drugs, social functioning, patterns of service use, residential stability, family support, and HIV risk behavior. Widespread abuse of substances known to cause psychotic symptoms has produced neuropsychiatric disorders that place new demands on the substance abuse and mental health service systems. Psychotic patients who use drugs have a need for treatment of their substance abuse. The diagnostic distinction between a substance-induced psychosis and a primary psychosis that co-occurs with drug use is of critical importance in planning for appropriate treatment. Greater knowledge of early psychosis and drug use in relation to illness course and outcome can lead to more effective assessment procedures, more appropriate matches to treatment for substance use, and uncover unmet needs for services.